Yahoo's news service still attracts very large volumes of
traffic. But other products, such as its search engine and email, have
suffered. The company's revenue from display advertising has also
dwindled.

'Shaping Google'

Interim CEO Ross Levinsohn was thought to have been the
favourite for the job before Monday's announcement that Ms Mayer was to
take the helm.

Correspondents say the selection of Ms Mayer to head the
company suggests a renewed focus on technology and products, over online
content.

"I look forward to working with the company's dedicated
employees to bring innovative products, content, and personalised
experiences to users and advertisers all around the world," Ms Mayer
said.

She becomes one of very few women in Silicon Valley to rise to the top of a major technology firm.

"A lot of people did not believe that Yahoo could get someone
of the caliber of a Marissa Mayer to become the CEO at this stage,"
Standard and Poor's equity analyst Scott Kessler told Reuters news
agency.

Ms Mayer, who takes up her post at Yahoo on Tuesday, joined Google in 1999 as the company's first female engineer.

A former computer science student at California's Stanford University, she was the fledgling company's 20th employee.

She worked on creating the Google search engine and the company's widely-recognised home page.

More recently, Ms Mayer has been in charge of the technology
giant's location and mapping services, which include Google Maps, Earth,
Local and Street View.

She has been credited with shaping much of the "look and feel" of Google's user experience.

Ms Mayer currently serves on the boards of Walmart, San
Francisco Museum of Modern Art, San Francisco Ballet and New York City
Ballet. She will also join Yahoo's board.